Unhindered Biplane-Shaped N-Heterocyclic Carbene Ligands as a Remedy for Low Reactivity of Crowded Substrates in Ruthenium Catalyzed Olefin Metathesis - Archive ouverte HAL Access content directly
Preprints, Working Papers, ... (Preprint) Year : 2023

Unhindered Biplane-Shaped N-Heterocyclic Carbene Ligands as a Remedy for Low Reactivity of Crowded Substrates in Ruthenium Catalyzed Olefin Metathesis

Abstract

Despite notable progress, olefin metathesis methods for preparing sterically crowded C-C double bonds remain scarce. They are commonly based on specialized ruthenium catalysts with sterically reduced N-heterocyclic carbene (NHC) ligands, able to accommodate more crowded olefinic sub-strates during the catalytic steps. Yet, although being highly active, these complexes are rather unstable, mainly due to intramolecular C-H activation at the ortho position of an N-aryl group of the NHC ligand, leading to catalyst deactivation. Considering that the deleterious C-H activation process requires the rotation of the N-aryl arm of the NHC ligand, we introduced a second decker of aromatic groups in benzimidazolylidene-based N-phenyl NHC ligands, which leads to robust and highly efficient ruthenium metathesis catalysts in challenging metathesis reactions of tri-and tetra-substituted olefins. The beneficial effect of these upper aromatic “wings” on the stability and activity of the Ru-complexes is rationalized through the experimental determination of the stereoelectronic properties of the NHC ligands, complemented by DFT calculations on the nature of the through-space interactions between the aromatics and on the decomposition pathway of the second-generation Hoveyda precursors.
Fichier principal
Vignette du fichier
Krzesinski, Unhindered Biplane-Shaped N-Heterocyclic, 2023.pdf (3.43 Mo) Télécharger le fichier
Raw data-20240411T062459Z-001.zip (235.04 Mo) Télécharger le fichier
Origin : Files produced by the author(s)
Licence : CC BY - Attribution

Dates and versions

hal-04542322 , version 1 (11-04-2024)

Licence

Attribution

Identifiers

Cite

Paweł Krzesiński, Chiara Dinoi, Iker Del rosal, Laure Vendier, Stéphanie Bastin, et al.. Unhindered Biplane-Shaped N-Heterocyclic Carbene Ligands as a Remedy for Low Reactivity of Crowded Substrates in Ruthenium Catalyzed Olefin Metathesis. 2024. ⟨hal-04542322⟩
42 View
5 Download

Altmetric

Share

Gmail Facebook X LinkedIn More